
/*******************************************************************************
 * Copyright IBM Corp. and others 1991
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 *******************************************************************************/

/**
 * @file
 * @ingroup GC_Structs
 */

#if !defined(CONSTANTPOOLCLASSSLOTITERATOR_HPP_)
#define CONSTANTPOOLCLASSSLOTITERATOR_HPP_

#include "j9.h"
#include "j9cfg.h"
#include "j9cp.h"
#include "modron.h"

/**
 * Iterate over class references (but not object references) in the constant pool of a class.
 * 
 * @see GC_ConstantPoolObjectSlotIterator
 * @ingroup GC_Structs
 */
class GC_ConstantPoolClassSlotIterator
{

	J9Object **_cpEntry;
	uint32_t _cpEntryCount;
	uint32_t _cpEntryTotal;
	uint32_t *_cpDescriptionSlots;
	uint32_t _cpDescription;
	uintptr_t _cpDescriptionIndex;
	
public:
	GC_ConstantPoolClassSlotIterator(J9Class *clazz)
		: _cpEntry((J9Object **)J9_CP_FROM_CLASS(clazz))
		, _cpEntryCount(clazz->romClass->ramConstantPoolCount)
	{
		_cpEntryTotal = _cpEntryCount;
		if (0 != _cpEntryCount) {
			_cpDescriptionSlots = SRP_PTR_GET(&clazz->romClass->cpShapeDescription, uint32_t *);
			_cpDescriptionIndex = 0;
		}
	}

	/**
	 * Gets the current constant pool index.
	 * @return zero based constant pool index of the entry returned by the last call of nextSlot.
	 * @return -1 if nextSlot has yet to be called.
	 */
	MMINLINE intptr_t getIndex() {
		return _cpEntryTotal - _cpEntryCount - 1;
	}

	J9Class *nextSlot();
};

#endif /* CONSTANTPOOLCLASSSLOTITERATOR_HPP_ */
